Method for manufacturing light guide plate having light scattering microstructures

Abstract

A method for manufacturing a light guide plate includes the follow steps. First, an injection mold including a cavity plate is provided. Then a plurality of microstructures is formed on the cavity plate by laser etching. Each microstructure includes a recess having a concave surface, and a protrusion formed around a periphery of the recess, wherein at least half of the concave surface is a mirror-like surface. Finally, a light guide plate is molded in the injection mold.

1. A method for manufacturing a light guide plate, the method comprising:
 providing an injection mold comprising a cavity plate; 
 forming a plurality of microstructures on the cavity plate by laser etching, each microstructure defining a substantially spherical recess having a concave surface, and a substantially ring-shaped protrusion formed around a periphery of the spherical recess, wherein at least half of the concave surface is a mirror-like surface; and 
 molding a light guide plate in the injection mold, wherein the light guide plate comprises a light input surface, a light output surface adjoining the light input surface, and a reflecting surface opposite the light output surface; at least one of the light output surface and the reflecting surface forms a plurality of substantially spherical protrusions corresponding to the plurality of substantially spherical recesses of the cavity plate, and a plurality of substantially ring-shaped grooves corresponding to the plurality of substantially ring-shaped protrusions of the cavity plate; each of the plurality of ring-shaped grooves is defined around a periphery of corresponding one of the plurality of spherical protrusions, and at least half of an outer surface of the plurality of spherical protrusions is a mirror-like surface. 
 
     
     
       2. The method for manufacturing a light guide plate of  claim 1 , wherein a laser light used for the laser etching is emitted by a neodymium-doped yttrium aluminum garnet laser. 
     
     
       3. The method for manufacturing a light guide plate of  claim 2 , wherein the wavelength of the laser light is in a range from about 1000 nanometers to about 1500 nanometers. 
     
     
       4. The method for manufacturing a light guide plate of  claim 3 , wherein the wavelength of the laser light is about 1064 nanometers. 
     
     
       5. The method for manufacturing a light guide plate of  claim 1 , wherein the light guide plate is made from material selected from the group consisting of polycarbonate, polymethyl methacrylate, polystyrene, copolymer of methylmethacrylate and styrene, and any combination thereof. 
     
     
       6. The method for manufacturing a light guide plate of  claim 1 , wherein a laser light used for the laser etching is emitted by a ruby laser. 
     
     
       7. The method for manufacturing a light guide plate of  claim 1 , wherein a laser light used for the laser etching is emitted by an alexandrite laser. 
     
     
       8. The method for manufacturing a light guide plate of  claim 6 , wherein the wavelength of the laser light is in a range from about 266 nanometers to about 532 nanometers. 
     
     
       9. The method for manufacturing a light guide plate of  claim 6 , wherein the wavelength of the laser light is in a range from about 266 nanometers to about 355 nanometers. 
     
     
       10. The method for manufacturing a light guide plate of  claim 6 , wherein the wavelength of the laser light is in a range from about 355 nanometers to about 532 nanometers. 
     
     
       11. The method for manufacturing a light guide plate of  claim 7 , wherein the wavelength of the laser light is in a range from about 266 nanometers to about 532 nanometers. 
     
     
       12. The method for manufacturing a light guide plate of  claim 7 , wherein the wavelength of the laser light is in a range from about 266 nanometers to about 355 nanometers. 
     
     
       13. The method for manufacturing a light guide plate of  claim 7 , wherein the wavelength of the laser light is in a range from about 355 nanometers to about 532 nanometers. 
     
     
       14. A method for manufacturing a light guide plate, the method comprising:
 providing an injection mold comprising a cavity plate; 
 forming a plurality of microstructures on the cavity plate by laser etching, each microstructure defining a substantially spherical recess having a concave surface, and a substantially ring-shaped protrusion formed around a periphery of the spherical recess, wherein at least half of the concave surface is a mirror-like surface; and 
 molding a light guide plate in the injection mold, wherein a major surface of the molded light guide plate comprises a plurality of light scattering microstructures, each of the plurality of light scattering microstructures comprising a spherical protrusion and a ring-shaped groove surrounding the spherical protrusion, the spherical protrusion and the ring-shaped groove corresponding to the spherical recess and the ring-shaped protrusion of a respective one of the plurality of microstructures of the cavity plate, wherein at least half of the spherical protrusion is as smooth as a mirror.